Add Windows process listing command ps

[caomengxuan666]

Summary

Users asking for kill also asked for a simple ps command, since terminating a process by PID is much easier when there is a native way to list processes first.

This came up in #45:

• Add Windows support for kill by process ID --from winuxcmd project #45 (comment) asked not to forget ps when adding kill
• Add Windows support for kill by process ID --from winuxcmd project #45 (comment) also asked for ps / kill because Windows command-line process management is hard to remember

ps is not GNU coreutils, so this should probably be treated as a Windows-specific convenience command rather than part of the strict coreutils set.

Proposed behavior

Add a small native Windows ps implementation that lists running processes, for example:

ps
ps -A
ps -e
ps aux
ps -p <PID>
ps --ppid <PID>
ps -o pid,ppid,comm

A minimal output could include PID, parent PID, and process image name. A few common filtering/formatting options would make it useful together with kill.

This should be implemented with Windows APIs rather than wrapping Sysinternals tools, so the package does not depend on external binaries.

For PowerShell integration, ps should also be added to the PSReadLine rewrite list so bare ps can be routed to ps.cmd in interactive PowerShell sessions, even though Get-Command ps may still show the built-in PowerShell alias.